# US 10,872,702 B2 · Stationary isolated rod couplings for use in a nuclear reactor control rod drive > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,702 B2 - Document ID: US10872702B2 - Status: Granted - Kind: B2 - Application number: 15/640,428 - Filed: 2017-06-30 - Published: 2018-01-18 - Granted: 2020-12-22 - Earliest claimed: 2016-07-13 - Assignees: GE-Hitachi Nuclear Energy Americas LLC - Applicants: GE-Hitachi Nuclear Energy Americas LLC - Inventors: Kenneth A. Morgan; David L. Major; Randy M. Brown - Web page: https://patentgrep.com/patent/US10872702B2 ## CPC - G21C 7/14: Mechanical drive arrangements - G21C 7/12: Means for moving control elements to desired position (dropping rods in an emergency G21C9/02) - G21C 9/02: Means for effecting very rapid reduction of the reactivity factor under fault conditions, e.g. reactor fuse; {Control elements having arrangements activated in an emergency}(control elements per se G21C7/00) - H02K 9/19: for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil - H02K 41/031: {of the permanent magnet type} - F16B 2200/83: Use of a magnetic material - G21C 17/10: Structural combination of fuel element, control rod, reactor core, or moderator structure with sensitive instruments, e.g. for measuring radioactivity, strain - Y02E 30/30: Nuclear fission reactors - G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J) - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate the magnetic fields across a full stroke length of the control element in the reactor. A closed coolant loop may cool the induction coils, which may be in a vacuum outside the isolation barrier. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Methods of operation include selectively energizing or de-energizing induction coils to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier. ## Claims ### Claim 1 A control rod drive for positioning a control element in a nuclear reactor, the drive comprising: an isolation barrier; an induction coil wound about an axis, wherein the axis is outside of the isolation barrier; a magnetic material inside the isolation barrier, wherein the material is configured to secure to the control element, and wherein the isolation barrier is impermeable to gasses and fluids such that a pressure gradient may be maintained across the inside and the outside of the isolation barrier; and a housing containing the induction coil and the isolation barrier, wherein the housing is configured to maintain a vacuum outside the isolation barrier. ### Claim 2 (depends on 1) The control rod drive of claim 1, further comprising: a plurality of the induction coils aligned in a length at least equal to an entire stroke distance of the control element. ### Claim 3 (depends on 2) The control rod drive of claim 2, wherein the plurality of induction coils includes a first induction coil and a second induction coil each wound about separate axes outside the isolation barrier. ### Claim 4 (depends on 1) The control drive of claim 1, further comprising: a closed coolant channel along the induction coil configured to carry a coolant flow to cool the induction coil. ### Claim 5 (depends on 1) The control rod drive of claim 1, wherein the induction coil is immobile and does not move with the magnetic material and control element. ### Claim 6 (depends on 1) The control rod drive of claim 1, wherein the magnetic material is at least one of a permanent magnet and an electromagnet, and wherein the material is positioned at a vertical end of an actuating rod of the control element. ### Claim 7 (depends on 1) The control rod drive of claim 1, further comprising: a coolant inlet and outlet in the housing. ### Claim 8 (depends on 1) The control rod drive of claim 1, further comprising: a plurality of magnetic overtravel latches inside the isolation barrier configured to hold the control element in an overtravel position; and a plurality of overtravel release coils outside the isolation barrier configured to move the overtravel latches into a release position. ### Claim 9 (depends on 8) The control rod drive of claim 8, wherein each of the magnetic overtravel latches includes a spring biasing the overtravel latch into a holding position, and wherein the overtravel release coils are configured to bias compress the spring through magnetic force. ### Claim 10 (depends on 1) The control rod drive of claim 1, further comprising: a control rod assembly in which the magnetic material is secured, wherein the control rod assembly includes a drive rod and lift rod, and wherein the control rod assembly is configured to directly join to the control element. ### Claim 11 A control rod drive for positioning a control element in a nuclear reactor, the drive comprising: an isolation barrier; an induction coil outside of the isolation barrier; a magnetic material inside the isolation barrier, wherein the material is configured to secure to the control element, and wherein the isolation barrier is impermeable to gasses and fluids such that a pressure gradient may be maintained across the inside and the outside of the isolation barrier; and a housing containing the induction coil and the isolation barrier, wherein the housing is configured to maintain a vacuum outside the isolation barrier. ### Claim 12 (depends on 11) The control rod drive of claim 11, further comprising: a coolant inlet and outlet in the housing. ### Claim 13 (depends on 11) The control rod drive of claim 11, further comprising: a plurality of the induction coils aligned in a length at least equal to an entire stroke distance of the control element. ### Claim 14 (depends on 11) The control drive of claim 11, further comprising: a closed coolant channel along the induction coil configured to carry a coolant flow to cool the induction coil. ### Claim 15 (depends on 11) The control rod drive of claim 11, wherein the induction coil is immobile and does not move with the magnetic material and control element. ### Claim 16 (depends on 11) The control rod drive of claim 11, wherein the magnetic material is at least one of a permanent magnet and an electromagnet, and wherein the material is positioned at a vertical end of an actuating rod of the control element. ### Claim 17 A control rod drive for positioning a control element in a nuclear reactor, the drive comprising: an isolation barrier; an induction coil outside of the isolation barrier; a magnetic material inside the isolation barrier, wherein the material is configured to secure to the control element, and wherein the isolation barrier is impermeable to gasses and fluids such that a pressure gradient may be maintained across the inside and the outside of the isolation barrier; a plurality of magnetic overtravel latches inside the isolation barrier configured to hold the control element in an overtravel position; and a plurality of overtravel release coils outside the isolation barrier configured to move the overtravel latches into a release position. ### Claim 18 (depends on 17) The control rod drive of claim 17, wherein each of the magnetic overtravel latches includes a spring biasing the overtravel latch into a holding position, and wherein the overtravel release coils are configured to bias compress the spring through magnetic force. ### Claim 19 (depends on 17) The control drive of claim 17, further comprising: a closed coolant channel along the induction coil configured to carry a coolant flow to cool the induction coil. ### Claim 20 (depends on 17) The control rod drive of claim 17, wherein the magnetic material is at least one of a permanent magnet and an electromagnet, and wherein the material is positioned at a vertical end of an actuating rod of the control element.